1. Field of the Invention
The invention relates to an inkjet printer including a sub-tank mounted on a printhead unit (carriage) and a main tank disposed in a main body of the inkjet printer and filled with ink to be supplied to the sub-tank. Particularly, the invention may be effectively applied to an inkjet printer adopting a station type ink supply system in which main and sub-tanks are connected to each other when ink is supplied from the main tank to the sub-tank, and the main and sub-tanks are otherwise disconnected from each other.
2. Description of Related Art
As disclosed in Japanese Laid-Open Patent Publication No. 2006-240039, sub-tanks mounted on a printhead unit are usually arranged side by side in a main scanning direction of the printhead unit such that adjacent two sub-tanks do not overlap, as seen from the front of an inkjet printer.
In order to reduce the size of a printhead unit in its main scanning direction, it is necessary to reduce a dimension of a mounting space for sub-tanks in a direction parallel to the main scanning direction. Hereinafter, this dimension is referred to as a mounting width of sub-tanks. When the sub-tank is made small in size, the amount of ink stored in the sub-tank might be reduced, necessitating frequent ink supplies from the main tank to the sub-tank and decreasing the benefit of having a sub-tank that is disconnectable from the main tank.
In view of the forgoing problem, it is an object of the invention to provide a printhead unit in which the mounting width of sub-tanks is made small without reducing the size of each sub-tank.